Abstract. We investigate fluid transport in random velocity fields
with unsteady drift. First, we propose to quantify
fluid transport between flow
regimes of different characteristic motion, by escape probability and mean
residence time.
We then develop numerical algorithms to solve for
escape probability and mean residence time,
which are described by
backward Fokker-Planck type partial differential equations.
A few computational issues are also discussed. Finally,
we apply these
ideas and numerical algorithms to
a tidal flow model.